| Message ID | 1333197516-5138-3-git-send-email-michael@walle.cc |
|---|---|
| State | Changes Requested |
| Delegated to: | Joe Hershberger |
| Headers | show |
On Saturday 31 March 2012 08:38:33 Michael Walle wrote: > --- a/include/net.h > +++ b/include/net.h > > in emergency cases, where you need a working network connection to seti "seti" -> "set" > + * Eg. you wan't a rescue boot and don't have a serial port to access "wan't" -> "want" > +void eth_random_enetaddr(uchar *enetaddr) > +{ > + uint32_t rval; > + > + srand(get_timer(0)); > + rval = rand(); > + > + enetaddr[0] = 0x02; /* locally administered */ > + enetaddr[1] = 0x00; > + enetaddr[2] = 0x00; > + enetaddr[3] = rval & 0xff; > + enetaddr[4] = (rval >> 8) & 0xff; > + enetaddr[5] = (rval >> 16) & 0xff; why only extract 24 of the 32bits ? and if you add a 2nd rand() call, you could seed all 48bits easily. then to make sure the first byte is correct, you finish off with: /* make sure it's local and unicast */ enetaddr[0] = (enetaddr[0] | 0x02) & ~0x01; -mike
Hi Mike, Am Sonntag 01 April 2012, 21:34:26 schrieb Mike Frysinger: > On Saturday 31 March 2012 08:38:33 Michael Walle wrote: > > --- a/include/net.h > > +++ b/include/net.h > > > > in emergency cases, where you need a working network connection to seti > > "seti" -> "set" > > > + * Eg. you wan't a rescue boot and don't have a serial port to access > > "wan't" -> "want" thanks ;) > > +void eth_random_enetaddr(uchar *enetaddr) > > +{ > > + uint32_t rval; > > + > > + srand(get_timer(0)); > > + rval = rand(); > > + > > + enetaddr[0] = 0x02; /* locally administered */ > > + enetaddr[1] = 0x00; > > + enetaddr[2] = 0x00; > > + enetaddr[3] = rval & 0xff; > > + enetaddr[4] = (rval >> 8) & 0xff; > > + enetaddr[5] = (rval >> 16) & 0xff; > > why only extract 24 of the 32bits ? couldn't find anything about OUIs and locally administered mac addresses, therefore i set the OUI to 0. But as this mac generation only applies to emergency cases, i guess it is better to have a smaller chance of duplicate mac addresses. > and if you add a 2nd rand() call, you > could seed all 48bits easily. yes, i'll rework that.
> -----Original Message----- > From: Michael Walle [mailto:michael@walle.cc] > Sent: 31 March 2012 18:09 > To: u-boot@lists.denx.de > Cc: Prafulla Wadaskar; Wolfgang Denk; Michael Walle > Subject: [PATCH 2/5] net: add helper to generate random mac address > > Add new function eth_random_enetaddr() to generate a locally > administered > ethernet address. > > Signed-off-by: Michael Walle <michael@walle.cc> > --- > include/net.h | 15 +++++++++++++++ > net/eth.c | 15 +++++++++++++++ > 2 files changed, 30 insertions(+), 0 deletions(-) This is standalone patch, Pls post it separately, it will be acked/picked by other custodian (net- copied) Regards.. Prafulla . . .
diff --git a/include/net.h b/include/net.h index 5560785..1fceb99 100644 --- a/include/net.h +++ b/include/net.h @@ -117,6 +117,21 @@ extern int eth_setenv_enetaddr(char *name, const uchar *enetaddr); extern int eth_getenv_enetaddr_by_index(const char *base_name, int index, uchar *enetaddr); +/* + * The u-boot policy does not allow hardcoded ethernet addresses. Under the + * following circumstances a random generated address is allowed: + * - in emergency cases, where you need a working network connection to seti + * the ethernet address. + * Eg. you wan't a rescue boot and don't have a serial port to access the + * CLI to set environment variables. + * + * In these cases, we generate a random locally administered ethernet address. + * + * Args: + * enetaddr - returns 6 byte hardware address + */ +extern void eth_random_enetaddr(uchar *enetaddr); + extern int usb_eth_initialize(bd_t *bi); extern int eth_init(bd_t *bis); /* Initialize the device */ extern int eth_send(volatile void *packet, int length); /* Send a packet */ diff --git a/net/eth.c b/net/eth.c index aabb343..4441969 100644 --- a/net/eth.c +++ b/net/eth.c @@ -70,6 +70,21 @@ static int eth_mac_skip(int index) return ((skip_state = getenv(enetvar)) != NULL); } +void eth_random_enetaddr(uchar *enetaddr) +{ + uint32_t rval; + + srand(get_timer(0)); + rval = rand(); + + enetaddr[0] = 0x02; /* locally administered */ + enetaddr[1] = 0x00; + enetaddr[2] = 0x00; + enetaddr[3] = rval & 0xff; + enetaddr[4] = (rval >> 8) & 0xff; + enetaddr[5] = (rval >> 16) & 0xff; +} + /* * CPU and board-specific Ethernet initializations. Aliased function * signals caller to move on
Add new function eth_random_enetaddr() to generate a locally administered ethernet address. Signed-off-by: Michael Walle <michael@walle.cc> --- include/net.h | 15 +++++++++++++++ net/eth.c | 15 +++++++++++++++ 2 files changed, 30 insertions(+), 0 deletions(-)